This catalogue is the latest incremental release of the DENIS project. It consists of a set of 355,220,325 point sources detected by the DENIS survey in 3662 strips (covering each 30 degrees in declination and 12 arcmin in right ascension). The data in this release cover approximately 16700 square degrees of the Southern sky. Multiple detections of single point sources have been merged in image overlaps within individual strips, but sources can have multiple detections in overlaping strips. DENIS is the only astronomical survey of the Southern sky made in two near-infrared bands (J at 1.25{mu}m, and K_s_ at 2.15{mu}m) and one optical band (Gunn-i at 0.82{mu}m), with limiting magnitudes 16.5, 14 and 18.5, respectively. Saturation magnitudes are K_s_=6, J=7.5 and Gunn-i=9.8mag. It was conducted by a European consortium, using the 1m telescope at ESO, La Silla (Chile). The DENIS instrument is made up of a 3-channel camera built of commercially available detector arrays by the Observatoire de Paris and with major contributions from other European Institutes, notably: the IAS in Frascati, the Observatoire de Grenoble, the University of Innsbruck, the Observatoire de Lyon, and the IAC in Tenerife. The survey is carried out by observing strips of 30{deg} in declination and 12arcminutes in Right Ascension with an overlap of 2 arcminutes between consecutive strips. The survey started at the end of 1995 and has been completed up to 97% in 2001. The data have been reduced at the Institut d'Astrophysique de Paris and Observatoire de Paris. The position of a general extracted point source is provided with an accuracy better than 1arcsec and its magnitude to better than 0.1 mag. The Centre de Donnees Astronomiques de Strasbourg (CDS) is releasing the final databases and provides access of the processed and calibrated data to the worldwide community. The principal investigator of the DENIS project is N. Epchtein (Observatoire de la Cote d'Azur); the Co-PI in charge of data processing is G. Simon (observatoire de Paris); J. Borsenberger and B. de Batz, with the help of F. Tanguy, S. Begon and P. Texier, processed the data and implemented the working data base at PDAC; S. Derriere is in charge of the data release at CDS. Scientists and engineers from seven European countries and from Brazil are involved in the data qualification and analysis.
This paper announces the release at CDS of a substantial set of point sources detected by the DENIS project. DENIS is the first astronomical survey of the Southern sky in two near-infrared bands (J at 1.25{mu}m, and K_s_ at 2.15{mu}m) and one optical band (Gunn-i at 0.82{mu}m), conducted by a European consortium, using the 1m telescope at ESO, La Silla (Chile). The first data release, described here, consists of a preliminary set of about 17 million extracted point sources, corresponding to 102 strips (2% of the Southern sky), and resulting from observations performed in 1996.
This catalogue is an intermediate release of the DENIS project. It consists of a set of 195204157 point sources detected by the DENIS survey in 2239 strips (covering each 30 degrees in declination and 12 arcmin in right ascension). The data in this release cover approximately 11000 square degrees of the Southern sky. Multiple detections of single point sources have been merged in image overlaps within individual strips, but sources can have multiple detections in overlapping strips. The complete set of data collected by DENIS in the period 1996-2001 will be released towards the end of 2003. DENIS is the only astronomical survey of the Southern sky made in two near-infrared bands (J at 1.25{mu}m, and K_s_ at 2.15{mu}m) and one optical band (Gunn-i at 0.82{mu}m), with limiting magnitudes 14.0, 16.5 and 18.5, respectively. It was conducted by a European consortium, using the 1m telescope at ESO, La Silla (Chile). The DENIS instrument is made up of a 3-channel camera built of commercially available detector arrays by the Observatoire de Paris and with major contributions from other European Institutes, notably: the IAS in Frascati, the Observatoire de Grenoble, the University of Innsbruck, the Observatoire de Lyon, and the IAC in Tenerife. The survey is carried out by observing strips of 30{deg} in declination and 12arcminutes in Right Ascension with an overlap of 2arcminutes between consecutive strips. The survey started at the end of 1995 and has been completed up to 97% in 2001. The data have been reduced at the Institut d'Astrophysique de Paris and Observatoire de Paris. The position of a general extracted point source is provided with an accuracy better than 1arcsec and its magnitude to better than 0.1mag. The Centre de Donnees Astronomiques de Strasbourg (CDS) is releasing the final databases and provides access of the processed and calibrated data to the worldwide community. The principal investigator of the DENIS project is N. Epchtein (Observatoire de la Cote d'Azur); the Co-PI in charge of data processing is G. Simon (observatoire de Paris); J. Borsenberger and B. de Batz, with the help of F. Tanguy, S. Begon and P. Texier, processed the data and implemented the working data base at PDAC; S. Derriere is in charge of the data release at CDS. Scientists and engineers from seven European countries and from Brazil are involved in the data qualification and analysis.
The 2dF Galaxy Redshift Survey (2dFGRS) is a major spectroscopic survey taking full advantage of the unique capabilities of the 2dF facility built by the Anglo-Australian Observatory. The 2dFGRS is integrated with the 2dF QSO survey (2QZ, Cat. VII/241). The 2dFGRS obtained spectra for 245591 objects, mainly galaxies, brighter than a nominal extinction-corrected magnitude limit of b_J_=19.45. Reliable (quality>=3) redshifts were obtained for 221414 galaxies. The galaxies cover an area of approximately 1500 square degrees selected from the extended APM Galaxy Survey in three regions: a North Galactic Pole (NGP) strip, a South Galactic Pole (SGP) strip, and random fields scattered around the SGP strip. Redshifts are measured from spectra covering 3600-8000 Angstroms at a two-pixel resolution of 9.0 Angstrom and a median S/N of 13 per pixel. All redshift identifications are visually checked and assigned a quality parameter Q in the range 1-5; Q>=3 redshifts are 98.4% reliable and have an rms uncertainty of 85 km/s. The overall redshift completeness for Q>=3 redshifts is 91.8% but this varies with magnitude from 99% for the brightest galaxies to 90% for objects at the survey limit. The 2dFGRS data base is available on the World Wide Web at http://www.mso.anu.edu.au/2dFGRS/.
We present the final spectroscopic QSO catalogue from the 2dF-SDSS LRG (luminous red galaxy) and QSO (2SLAQ) survey. This is a deep, 18<g<21.85 (extinction corrected), sample aimed at probing in detail the faint end of the broad line active galactic nuclei luminosity distribution at z<=2.6. The candidate QSOs were selected from SDSS photometry and observed spectroscopically with the 2dF spectrograph on the Anglo-Australian Telescope. This sample covers an area of 191.9 deg2 and contains new spectra of 16326 objects, of which 8764 are QSOs and 7623 are newly discovered [the remainder were previously identified by the 2dF QSO Redshift Survey (2QZ) and SDSS]. The full QSO sample (including objects previously observed in the SDSS and 2QZ surveys) contains 12702 QSOs. The new 2SLAQ spectroscopic data set also contains 2343 Galactic stars, including 362 white dwarfs, and 2924 narrow emission-line galaxies with a median redshift of z=0.22.
We use double-mode RR Lyrae (RRd) stars from the MACHO variable star database of the Large Magellanic Cloud (LMC) to estimate its distance, by utilizing photometric data, linear pulsation and stellar atmosphere models. If we set E_(B-V)_=0.11 and [M/H]=-1.5 for LMC, we get M-m=18.52mag. The fact that the distance moduli obtained in this and in our former studies of cluster RRd and Small Magellanic Cloud beat Cepheids agree so well, implies that the only serious source of error is the zero point of the temperature scale, which should not have larger than +/-0.10mag effect on the distance modulus.
We present the North Galactic Cap sample of the Extremely Luminous Quasar Survey (ELQS-N), which targets quasars with M_1450_{<}-27 at 2.8<=z<5 in an area of ~7600deg^2^ of the Sloan Digital Sky Survey (SDSS) footprint with 90{deg}<RA<270{deg}. Based on a near-infrared/infrared JKW2 color cut, the ELQS selection efficiently uses random forest methods to classify quasars and to estimate photometric redshifts; this scheme overcomes some of the difficulties of pure optical quasar selection at z~3. As a result, we retain a completeness of >70% over z~3.0-5.0 at m_i_<~17.5, limited toward fainter magnitudes by the depth of the Two Micron All Sky Survey. The presented quasar catalog consists of a total of 270 objects, of which 39 are newly identified in this work with spectroscopy obtained at the Vatican Advanced Technology Telescope and the MMT 6.5m telescope. In addition to the high completeness, which allowed us to discover new quasars in the already well-surveyed SDSS North Galactic Cap, the efficiency of our selection is relatively high at ~79%. Using 120 objects of this quasar sample we are able to extend the previously measured optical quasar luminosity function (QLF) by one magnitude toward the bright end at 2.8<=z<=4.5. A first analysis of the QLF suggests a relatively steep bright-end slope of {beta}~-4 for this sample. This result contrasts with previous results in the same redshift range, which find a much flatter slope around {beta}~-2.5, but agrees with recent measurements of the bright-end slope at lower and higher redshifts. Our results constrain the bright-end slope at z=2.8-4.5 to {beta}{<}-2.94 with a 99% confidence.
We present the results of the Extremely Luminous Quasar Survey in the 3{pi} survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS; PS1). This effort applies the successful quasar selection strategy of the Extremely Luminous Survey in the Sloan Digital Sky Survey footprint (~12000deg^2^) to a much larger area (~21486deg^2^). This spectroscopic survey targets the most luminous quasars (M_1450_<=-26.5; m_i_<=18.5) at intermediate redshifts (z>=2.8). Candidates are selected based on a near-infrared JKW2 color cut using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants. Photometric redshifts (z_reg_) and star-quasar classifications for each candidate are calculated from near-infrared and optical photometry using the supervised machine learning technique random forests. We select 806 quasar candidates at z_reg_>=2.8 from a parent sample of 74318 sources. After exclusion of known sources and rejection of candidates with unreliable photometry, we have taken optical identification spectra for 290 of our 334 good PS-ELQS candidates. We report the discovery of 190 new z>=2.8 quasars and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS candidates remain unobserved. Including all known quasars at z>=2.8, our quasar selection method has a selection efficiency of at least 77%. At lower declinations, -30<=DEC<=0, we approximately treble the known population of extremely luminous quasars. We provide the PS-ELQS quasar catalog with a total of 592 luminous quasars (m_i_<=18.5, z>=2.8). This unique sample will not only be able to provide constraints on the volume density and quasar clustering of extremely luminous quasars, but also offers valuable targets for studies of the intergalactic medium.
We present results on a survey to find extremely dust-reddened Type 1 quasars. Combining the FIRST radio survey, the 2MASS Infrared Survey and the Sloan Digital Sky Survey, we have selected a candidate list of 122 potential red quasars. With more than 80% spectroscopically identified objects, well over 50% are classified as dust-reddened Type 1 quasars, whose reddenings (E(B-V)) range from approximately 0.1 to 1.5mag. They lie well off the color selection windows usually used to detect quasars and many fall within the stellar locus, which would have made it impossible to find these objects with traditional color selection techniques. The reddenings found are much more consistent with obscuration happening in the host galaxy rather than stemming from the dust torus. We find an unusually high fraction of broad absorption line (BAL) quasars at high redshift, all but one of them belonging to the low-ionization BAL (LoBAL) class and many also showing absorption in the metastable FeII line (FeLoBAL). The discovery of further examples of dust-reddened LoBAL quasars provides more support for the hypothesis that BAL quasars (at least LoBAL quasars) represent an early stage in the lifetime of the quasar. The fact that we see such a high fraction of BALs could indicate that the quasar is in a young phase in which quasar feedback from the BAL winds is suppressing star formation in the host galaxy.
We present a statistical analysis of the first 300 stars observed by the Gemini Planet Imager Exoplanet Survey. This subsample includes six detected planets and three brown dwarfs; from these detections and our contrast curves we infer the underlying distributions of substellar companions with respect to their mass, semimajor axis, and host stellar mass. We uncover a strong correlation between planet occurrence rate and host star mass, with stars M_*_>1.5 M_{sun}_ more likely to host planets with masses between 2 and 13 M_Jup_ and semimajor axes of 3-100 au at 99.92% confidence. We fit a double power-law model in planet mass (m) and semimajor axis (a) for planet populations around high-mass stars (M_*_>1.5 M_{sun}_) of the form d^2^N/(dm da){prop.to}m^{alpha}^{alpha}^{beta}^, finding {alpha}=-2.4+/-0.8 and {beta}=-2.0+/-0.5, and an integrated occurrence rate of 9_-4_^+5^% between 5-13 M_Jup_ and 10-100 au. A significantly lower occurrence rate is obtained for brown dwarfs around all stars, with 0.8_-0.5_^+0.8^% of stars hosting a brown dwarf companion between 13-80 M_Jup_ and 10-100 au. Brown dwarfs also appear to be distributed differently in mass and semimajor axis compared to giant planets; whereas giant planets follow a bottom-heavy mass distribution and favor smaller semimajor axes, brown dwarfs exhibit just the opposite behaviors. Comparing to studies of short-period giant planets from the radial velocity method, our results are consistent with a peak in occurrence of giant planets between ~1 and 10 au. We discuss how these trends, including the preference of giant planets for high-mass host stars, point to formation of giant planets by core/pebble accretion, and formation of brown dwarfs by gravitational instability.